三数最大值查找程序故障求助：文件关联问题排查

Hey there! Let's break down why your program isn't running and fix it step by step:

The Critical Error in Your JavaScript #

The main issue is a tiny but impactful oversight in the first line of your JS code. Take a look:

// ❌ Wrong: getElementById isn't a global function
let pressedKey = getElementById("button");

getElementById() is a method that belongs to the document object—you can't call it on its own. This throws a reference error that stops your entire script from executing before it even gets to the click event logic.

Fixed JavaScript Code #

Here's the corrected JS with that fix, plus an extra check for invalid inputs (to handle cases where users enter non-numeric values, which would break your current logic):

// ✅ Correct: Use document.getElementById()
let pressedKey = document.getElementById("button");
pressedKey.addEventListener("click",function() {
 let num1 = Number(document.getElementById("num1").value);
 let num2 = Number(document.getElementById("num2").value);
 let num3 = Number(document.getElementById("num3").value);

 // Add this to catch non-numeric inputs
 if (isNaN(num1) || isNaN(num2) || isNaN(num3)) {
   window.alert("Oops! Please enter valid numbers for all three fields.");
   return; // Stop the function here if inputs are invalid
 }

 if (num1 > num2 && num1 > num3) {
 window.alert(num1 + " is the greatest!");
 } else if (num2 > num1 && num2 > num3) {
 window.alert(num2 + " is the greatest!");
 } else {
 window.alert(num3 + " is the greatest!");
 }
});

Quick Check for File Paths #

Make sure your greatestNumber.js file is saved in the same folder as your HTML file. If you put it in a subfolder (like a js/ directory), update your script tag to match the path:

<script src="js/greatestNumber.js"></script>

Minor HTML Tweak (Optional) #

Your HTML works perfectly fine, but just a quick standardization note: HTML input tags are self-closing, so you don't need </input>—you can write them like this instead (it's more widely accepted practice):

Enter number one: <input type="text" id="num1"><br>
Enter number two: <input type="text" id="num2"><br>
Enter number three: <input type="text" id="num3"><br>

With these fixes, your program should run smoothly when you click the "OK" button!

内容的提问来源于stack exchange，提问作者Lubak